143 research outputs found
Corrigendum to Characterization of westward propagating signals in the South Atlantic from altimeter and radiometer records ”[Remote Sens. Environ., 134: 367-376]
Radar altimeter data from TOPEX/Poseidon and Jason-1 and microwave radiometer data from TRMM/TMI are used to investigate the large-scale variability between 10.5°S and 35.5°S in the South Atlantic Ocean. The proposed method for the analysis of the longitude–time diagrams of the cross-correlation between SSH and SST anomalies shows that the variability in mid latitudes is a blend of first-mode baroclinic Rossby waves and propagating mesoscale eddy-like structures. The estimated phase speed of the wave (cp) and propagation speed of the eddies (cv) are similar. In 70% of the cases, the absolute difference between cp and cv is less than 11%. In 40% of the cases this difference is less than 5%. Statistical results indicate that in the case of eddies, as the thermocline deepens the sea surface temperature rises and vice-versa. However, planetary waves show more complex, yet self-consistent results. In lower latitudes (10.5°S–15.5°S), the shallower thermocline and the weak thermal gradients impose a zero phase lag between temperature and height, similar to eddies. Poleward of those latitudes, sea surface temperature and height are in quadrature of phase. This indicates that geostrophic advection of the relatively stronger thermal gradient is performed by Rossby wave
Efecto de extractos de hojas y frutos de Schinus molle sobre la estabilidad oxidativa de aceites mediante oxidación acelerada
The most highly recommended oils for the diet are those which are rich in unsaturated fatty acids. However, the presence of these components in the oils is related to oxidation, which can be determined by the induction period. Further safety and the prolongation of the storage period for such oils can be achieved by the addition of efficient antioxidants, which today are preferably from natural sources. In order to contribute to the related research, the main objective of this study was to evaluate the efficacy of Schinus molle extracts compared to synthetic antioxidants (BHT) in delaying the oxidation of some vegetable oils. The results of the present study showed that the fruit and leaf extracts of Schinus molle presented activities and potential for being used as antioxidants in vegetable oils based on the tested methods (DPPH and ABTS). The extracts were also characterized as containing phenolic compounds by the Folin Ciocalteau method and by high performance liquid chromatography (HPLC). The action of the extracts as natural antioxidants was proven in the vegetal oils of chia (Salvia hispanica) and peanut (Arachis hypogaea) by the Rancimat method. It was observed that the oils increased their resistance to oxidation when incorporated with the extracts of Schinus molle, and the extract from the leaves increased the induction period of peanut oil by more than three hours (from 19.5 to 22.9 hours) with an extract concentration of 2.5%. The fruit extract was more efficient in delaying the oxidation of chia oil, prolonging its induction period by more than one hour with a concentration of 2.5% (from 3.1 to 4.3 hours). According to the results, the extracts of Schinus molle have favorable properties for possible use as an additive which inhibits the oxidation process of the tested vegetables oils.Los aceites más recomendados para la dieta son los ricos en ácidos grasos insaturados. Sin embargo, la presencia de estos componentes está relacionada con la oxidación del aceite, que puede determinarse por el período de inducción. La seguridad adicional de tales aceites y la prolongación del almacenamiento se pueden lograr mediante la adición de antioxidantes eficientes, que hoy en día se prefieren los provenientes de fuentes naturales. Para contribuir con estas investigaciones, el objetivo principal de este estudio fue evaluar la eficacia de los extractos de Schinus molle en comparación con el antioxidante sintético BHT, para retrasar la oxidación de algunos aceites vegetales. Los resultados del presente estudio mostraron que los extractos de frutas y hojas de Schinus molle presentan potencial para ser utilizados como antioxidantes en aceites vegetales, presentando actividades basadas en métodos probados, DPPH y ABTS. Los extractos también se caracterizaron por la presencia de compuestos fenólicos determinados mediante el método de Folin Ciocalteau y por cromatografía líquida de alta resolución (HPLC). La acción de los extractos como antioxidantes naturales se evidenció en aceites vegetales de chía (Salvia hispanica) y maní (Arachis hypogaea) por el método Rancimat. Se observó que los aceites aumentan la resistencia a la oxidación cuando se le incorporan extractos de Schinus molle, aumentando el periodo de inducción en más de tres horas (de 19,5 a 22,9 horas) del aceite de cacahuete con una concentración de extracto del 2,5%. El extracto de fruta fue más eficiente en retrasar la oxidación del aceite de chia, prolongando el período de inducción de este aceite en más de una hora con una concentración del 2,5% (de 3,1 a 4,3 horas). De acuerdo con los resultados, los extractos de Schinus molle tienen propiedades favorables para un posible uso como un aditivo inhibidor del proceso de oxidación de los aceites vegetales ensayados
(R)-(-)-carvone and (1R, 4R)-trans-(+)-dihydrocarvone from poiretia latifolia vogel
The essential oils of Poiretia latifolia Vogel, native and cultivated leaves (Samples A and B, respectively) and native flowers (sample C), were obtained by hydrodistillation and analyzed by GC, GC/MS and chiral phase gas chromatography (CPGC). Twenty-four compounds were identified, representing 99.25, 99.26 and 99.23% of the oils, respectively. The major constituents of the oils were the monoterpenes (S)-(-)-limonene (16.05, 27.60, 15.60%, respectively), (1R, 4R)-trans-(+)-dihydrocarvone (18.05, 0.66 and 77.80%, respectively) and (R)-(-)-carvone (61.05, 64.20 and 4.50%, respectively). The essential oils were evaluated against some strains of Gram (+) and Gram (-) bacteria, and yeast, but displayed only modest antimicrobial activity
Ultrasound-Promoted Synthesis of 3-(Thiophen-2-yl)-4,5-dihydro-1H-pyrazole-1carboximidamides and Anticancer Activity Evaluation in Leukemia Cell Lines
3-(Thiophen-2-yl)-4,5-dihydro-1H-pyrazole-1-carboximidamides were efficiently prepared through a cyclocondensation of thiophenylchalcones with aminoguanidine hydrochloride under ultrasonic conditions in the presence of KOH and ethanol as a green solvent in short reaction times (15-35 min) and good yields (62-95%). All compounds produced were evaluated against the human Jurkat and RS411 acute lymphoblastic leukemia cell lines of T- and B-cell origin, respectively, and the K562 myelogenous leukemia cell line. Six compounds presented half maximal inhibitory concentration (IC50) values around 15 mu mol L-1 and five compounds presented IC50 values around 40 mu mol L-1 for at least one of the three cell lines analyzed. One compound was not significantly cytotoxic, presenting IC50 value > 100 mu mol L- 1.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Fundacao de Apoio ao Desenvolvimento do Ensino, Ciencia e Tecnologia do Estado de Mato Grosso do Sul (FUNDECT)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)FAPESPCNPqFundacao Univ Fed Grande Dourados, Grp Pesquisa Sintese & Caracterizacao Mol MS, Rua Joao Rosa Goes 1761, BR-79825070 Dourados, MS, BrazilUniv Estadual Campinas, Inst Biol, Dept Genet & Biol Mol, Rua Monteiro Lobato 255, BR-13083970 Campinas, SP, BrazilCtr Infantil Boldrini, Mol Biol Lab, Rua Dr Gabriel Porto 1270, BR-13083210 Campinas, SP, BrazilUniv Fed Sao Paulo, Dept Ciencias Exatas & Terra, Rua Prof Artur Riedel 275, BR-09972270 Diadema, SP, BrazilUniv Fed Pelotas, Ctr Ciencias Quim Farmaceut & Alimentos, Lab Lipid & Bioorgan, Campus Univ, BR-96001900 Pelotas, RS, BrazilUniv Estadual Mato Grosso do Sul, Rua Emilio Mascolli 275, BR-79950000 Navirai, MS, BrazilUniv Fed Sao Paulo, Dept Ciencias Exatas & Terra, Rua Prof Artur Riedel 275, BR-09972270 Diadema, SP, BrazilCNPq: 483021/2013-0FUNDECT: 0180/12FAPESP: 12/12802-1Web of Scienc
Deeply virtual and exclusive electroproduction of omega mesons
The exclusive omega electroproduction off the proton was studied in a large
kinematical domain above the nucleon resonance region and for the highest
possible photon virtuality (Q2) with the 5.75 GeV beam at CEBAF and the CLAS
spectrometer. Cross sections were measured up to large values of the
four-momentum transfer (-t < 2.7 GeV2) to the proton. The contributions of the
interference terms sigma_TT and sigma_TL to the cross sections, as well as an
analysis of the omega spin density matrix, indicate that helicity is not
conserved in this process. The t-channel pi0 exchange, or more generally the
exchange of the associated Regge trajectory, seems to dominate the reaction
gamma* p -> omega p, even for Q2 as large as 5 GeV2. Contributions of handbag
diagrams, related to Generalized Parton Distributions in the nucleon, are
therefore difficult to extract for this process. Remarkably, the high-t
behaviour of the cross sections is nearly Q2-independent, which may be
interpreted as a coupling of the photon to a point-like object in this
kinematical limit.Comment: 15 pages,19 figure
Q^2 Dependence of the S_{11}(1535) Photocoupling and Evidence for a P-wave resonance in eta electroproduction
New cross sections for the reaction are reported for total
center of mass energy =1.5--2.3 GeV and invariant squared momentum transfer
=0.13--3.3 GeV. This large kinematic range allows extraction of new
information about response functions, photocouplings, and coupling
strengths of baryon resonances. A sharp structure is seen at 1.7 GeV.
The shape of the differential cross section is indicative of the presence of a
-wave resonance that persists to high . Improved values are derived for
the photon coupling amplitude for the (1535) resonance. The new data
greatly expands the range covered and an interpretation of all data with
a consistent parameterization is provided.Comment: 31 pages, 9 figure
Chemical Composition and Evaluation of Antitumoral Activity of Leaf and Root Essential Oils of Conyza canadensis (Asteraceae)
The leaf and root oils of Conyza canadensis were studied for chemical composition and antitumor activity. The results showed that there is great variation in the composition of the oils obtained from different parts. The main components in the leaf oil were limonene, caryophyllene oxide and espatulenol. In the root oil the major component was the acetylenic ester lachnophyllum methyl ester. It was observed that according to the collection time (6 and 16 hours), significant variations in the content of the main components of this essential oil of leaves can occur. Limonene, spatulenol and caryophyllene oxide presented a distribution of 61% / 5.4% / 12.5% and 38% / 10.7% / 22.3% in oils obtained from plants collected at 6 and 16 hours, respectively. The antitumor activity of the oils showed that leaf oil had a greater potential for inhibition, and this oil was distinguished by the activity against neoplastic cell lines K562 (leukemia) and NCI-ADR / RES (ovary with multidrug resistance phenotype ) with TGI values of 16.8 and 19.0 mg.mL-1, respectively. Comparing the leaf oils and their tumor cell inhibition potentials, it was noted that this activity is higher in the oil with higher contents of monoterpene limonene.
DOI: http://dx.doi.org/10.17807/orbital.v11i5.137
Measurement of Inclusive Spin Structure Functions of the Deuteron
We report the results of a new measurement of spin structure functions of the
deuteron in the region of moderate momentum transfer ( = 0.27 -- 1.3
(GeV/c)) and final hadronic state mass in the nucleon resonance region (
= 1.08 -- 2.0 GeV). We scattered a 2.5 GeV polarized continuous electron beam
at Jefferson Lab off a dynamically polarized cryogenic solid state target
(ND) and detected the scattered electrons with the CEBAF Large
Acceptance Spectrometer (CLAS). From our data, we extract the longitudinal
double spin asymmetry and the spin structure function . Our
data are generally in reasonable agreement with existing data from SLAC where
they overlap, and they represent a substantial improvement in statistical
precision. We compare our results with expectations for resonance asymmetries
and extrapolated deep inelastic scaling results. Finally, we evaluate the first
moment of the structure function and study its approach to both the
deep inelastic limit at large and to the Gerasimov-Drell-Hearn sum rule
at the real photon limit (). We find that the first moment varies
rapidly in the range of our experiment and crosses zero at between
0.5 and 0.8 (GeV/c), indicating the importance of the resonance at
these momentum transfers.Comment: 13 pages, 8 figures, ReVTeX 4, final version as accepted by Phys.
Rev.
Measurement of the Polarized Structure Function for in the Resonance Region
The polarized longitudinal-transverse structure function
has been measured using the reaction in the
resonance region at and 0.65 GeV. No previous
data exist for this reaction channel. The kinematically
complete experiment was performed at Jefferson Lab with the CEBAF Large
Acceptance Spectrometer (CLAS) using longitudinally polarized electrons at an
energy of 1.515 GeV. A partial wave analysis of the data shows generally better
agreement with recent phenomenological models of pion electroproduction
compared to the previously measured channel. A fit to both
and channels using a unitary isobar model suggests the unitarized
Born terms provide a consistent description of the non-resonant background. The
-channel pion pole term is important in the channel through a
rescattering correction, which could be model-dependent.Comment: 6 pages, LaTex, 5 eps figures: Submitted to PRC/Brief Reports v2:
Updated referenc
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